<template>
  <div style="padding: 10px; margin-bottom: 50px">
    <el-row>
      <el-col :span="4">
        <el-card style="width: 300px; height: 300px; color: #333">
          <div style="padding-bottom: 10px; border-bottom: 1px solid #ccc">
            在线用户
            <span style="font-size: 12px">（点击聊天气泡开始聊天）</span>
          </div>
          <div style="padding: 10px 0" v-for="user in users" :key="user.realname">
            <span>{{ user.realname }}</span>
            <i
              class="el-icon-chat-dot-round"
              style="margin-left: 10px; font-size: 16px; cursor: pointer"
              @click="chatUser = user.realname"
            ></i>
            <span style="font-size: 12px; color: limegreen; margin-left: 5px" v-if="user.realname === chatUser">
              chatting...
            </span>
          </div>
        </el-card>
      </el-col>

      <el-col :span="20">
        <div
          style="width: 800px; margin: 0 auto; background-color: white; border-radius: 5px; box-shadow: 0 0 10px #ccc"
        >
          <div style="text-align: center; line-height: 50px">Web聊天室（{{ chatUser }}）</div>
          <div style="height: 350px; overflow: auto; border-top: 1px solid #ccc" v-html="content"></div>
          <div style="text-align: left; padding-left: 20px">
            <span style="color: gray; font-size: 16px">Ctrl+Enter为换行 回车即发送</span>
          </div>
          <div style="height: 200px">
            <el-input
              type="textarea"
              v-model="text"
              style="width: 760px; padding: 20px"
              :rows="5"
              resize="none"
              @keydown.enter.native="keyDown"
            ></el-input>
            <div style="text-align: right; padding-right: 10px; margin-top: 5px">
              <el-button type="primary" size="mini" @click="send">发送</el-button>
            </div>
          </div>
        </div>
      </el-col>
    </el-row>
  </div>
</template>

<script>
let socket
export default {
  name: 'Im',
  data() {
    return {
      circleUrl: 'https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png',
      user: {},
      isCollapse: false,
      users: [],
      chatUser: '',
      text: '',
      messages: [],
      content: ''
    }
  },
  created() {
    this.init()
  },
  methods: {
    send() {
      if (!this.chatUser) {
        this.$message({ type: 'warning', message: '请选择聊天对象' })
        return
      }
      if (!this.text) {
        this.$message({ type: 'warning', message: '请输入内容' })
      } else {
        if (typeof WebSocket == 'undefined') {
          this.$message.error('您的浏览器不支持WebSocket')
        } else {
          console.log('您的浏览器支持WebSocket')
          // 组装待发送的消息 json
          // {"from": "zhang", "to": "admin", "text": "聊天文本", "fromImg": "http://....."}
          let message = { from: this.user.realname, to: this.chatUser, text: this.text, fromImg: this.user.userFace }
          socket.send(JSON.stringify(message)) // 将组装好的json发送给服务端，由服务端进行转发
          this.messages.push({ user: this.user.realname, text: this.text })
          // 构建消息内容，本人消息
          this.createContent(null, this.user.realname, this.text, this.user.userFace)
          this.text = ''
        }
      }
    },
    createContent(remoteUser, nowUser, text, img) {
      // 这个方法是用来将 json的聊天消息数据转换成 html的。
      if (img === null || img === undefined || img === '') {
        img = 'https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png'
      }
      let html
      // 当前用户消息
      if (nowUser) {
        // nowUser 表示是否显示当前用户发送的聊天消息，绿色气泡
        html =
          '<div class="el-row" style="padding: 5px 0">\n' +
          '  <div class="el-col el-col-22" style="text-align: right; padding-right: 10px">\n' +
          '    <div class="tip left">' +
          text +
          '</div>\n' +
          '  </div>\n' +
          '  <div class="el-col el-col-2">\n' +
          '  <span class="el-avatar el-avatar--circle" style="height: 40px; width: 40px; line-height: 40px;">\n' +
          '    <img src="' +
          img +
          '" style="object-fit: cover;">\n' +
          '  </span>\n' +
          '  </div>\n' +
          '</div>'
      } else if (remoteUser) {
        // remoteUser表示远程用户聊天消息，蓝色的气泡
        html =
          '<div class="el-row" style="padding: 5px 0">\n' +
          '  <div class="el-col el-col-2" style="text-align: right">\n' +
          '  <span class="el-avatar el-avatar--circle" style="height: 40px; width: 40px; line-height: 40px;">\n' +
          '    <img src="' +
          img +
          '" style="object-fit: cover;">\n' +
          '  </span>\n' +
          '  </div>\n' +
          '  <div class="el-col el-col-22" style="text-align: left; padding-left: 10px">\n' +
          '    <div class="tip right">' +
          text +
          '</div>\n' +
          '  </div>\n' +
          '</div>'
      }
      console.log(html)
      this.content += html
    },
    init() {
      this.user = sessionStorage.getItem('role') ? JSON.parse(sessionStorage.getItem('role')) : {}
      let realname = this.user.realname
      let _this = this
      if (typeof WebSocket == 'undefined') {
        this.$message.error('您的浏览器不支持WebSocket')
      } else {
        console.log('您的浏览器支持WebSocket')
        let socketUrl = 'ws://111.231.71.116:10010/imserver/' + realname
        if (socket != null) {
          socket.close()
          socket = null
        }
        // 开启一个websocket服务
        socket = new WebSocket(socketUrl)
        //打开事件
        socket.onopen = function () {
          console.log('websocket已打开')
        }
        //  浏览器端收消息，获得从服务端发送过来的文本消息
        socket.onmessage = function (msg) {
          console.log('收到数据====' + msg.data)
          let data = JSON.parse(msg.data) // 对收到的json数据进行解析， 类似这样的： {"users": [{"realname": "zhang"},{ "realname": "admin"}]}
          if (data.users) {
            // 获取在线人员信息
            _this.users = data.users.filter((user) => user.realname !== realname) // 获取当前连接的所有用户信息，并且排除自身，自己不会出现在自己的聊天列表里
          } else {
            // 如果服务器端发送过来的json数据 不包含 users 这个key，那么发送过来的就是聊天文本json数据
            //  // {"from": "zhang", "text": "hello", "img": ""}
            if (data.from === _this.chatUser) {
              _this.messages.push(data)
              // 构建消息内容
              _this.createContent(data.from, null, data.text, data.img)
            }
          }
        }
        //关闭事件
        socket.onclose = function () {
          console.log('websocket已关闭')
        }
        //发生了错误事件
        socket.onerror = function () {
          console.log('websocket发生了错误')
        }
      }
    },
    keyDown(e) {
      if (e.ctrlKey && e.keyCode === 13) {
        // ctrl+enter触发
        this.text += '\n'
      } else {
        // enter触发
        e.preventDefault() // 阻止默认的换行操作
        this.send()
      }
    }
  }
}
</script>

<style>
.tip {
  color: white;
  text-align: center;
  border-radius: 10px;
  font-family: sans-serif;
  padding: 10px;
  width: auto;
  display: inline-block !important;
  display: inline;
}

.right {
  background-color: deepskyblue;
}
.left {
  background-color: forestgreen;
}
</style>
